python script to accept 8 char password with these conditions only: 2 num, 2 upper, 2 lower, and 2 special

Question

This is what I've done till now. And when it goes wrong it doesn't print 'Not Okay'. I'm still not able to figure out how to check special chars.

#!/usr/bin/python

def passw_check():
    passin = raw_input("Enter the password")

    if len(passin) == 8:       # checking total length of password
        if sum(map(str.isupper, passin))== 2: #check 2 upper chars
            if sum(map(str.islower, passin))== 2:  #check 2 lower chars
                if sum(map(str.isdigit, passin))== 4:  #check 2 digits chars
                    print 'Passwords Okay'
                else: 
                    print 'Not Okay!'

passw_check()

Well, your else is only associated with your final IF. You need to be clear in your question whether you have two problems or one. — Bill Woodger, Apr 04 '15 at 15:05
Then, should it be in indented with first IF, because/if they are nested? Yes you are right my if-else loop is not working correctly. — sunp, Apr 04 '15 at 15:08
I hope you're [not actually trying to apply](http://stackoverflow.com/questions/98768/should-i-impose-a-maximum-length-on-passwords) those [password restrictions](http://security.stackexchange.com/questions/33470/what-technical-reasons-are-there-to-have-low-maximum-password-lengths) on a real public system. — Ilmari Karonen, Apr 04 '15 at 15:15
@llmari karonen, It will only make things safer on internet, isn't it? Not really, its for my personal script only! hey! — sunp, Apr 04 '15 at 15:25

score 1 · Answer 1 · answered Apr 04 '15 at 15:06

Only the innermost if has an else-branch. Use and to check all conditions at once:

def passw_check():
    passin = raw_input("Enter the password")

    if (len(passin) == 8 and       # checking total length of password
        sum(map(str.isupper, passin)) == 2 and #check 2 upper chars
        sum(map(str.islower, passin)) == 2 and  #check 2 lower chars
        sum(map(str.isdigit, passin))== 4):  #check 2 digits chars
        print 'Passwords Okay'
    else: 
        print 'Not Okay!'
    return passin

passw = passw_check()

jedwards · Accepted Answer · 2015-04-04T15:15:50.887

I'd probably do something like:

#!/usr/bin/python
import string

def validate(s):
    def is_punc(c): return c in string.punctuation
    if len(s) != 8:                   return False
    if sum(map(str.isupper, s)) != 2: return False
    if sum(map(str.islower, s)) != 2: return False
    if sum(map(str.isdigit, s)) != 2: return False
    if sum(map(is_punc, s))     != 2: return False
    # Note of the tests have been violated, return True
    return True


def passw_check():
    passin = raw_input("Enter the password: ")

    if validate(passin):
        print 'Passwords Okay'
    else:
        print 'Not Okay!'

passw_check()

Here, the validate function is very clear and the logic is easy to understand.

Also note, you say you only want 2 numeric characters, but the test in your code checks for 4. I changed this to 2 to fit your problem description, just a heads up.

Edit Added string.punctuation test instead of just assuming the non-alphanum characters are "special" -- this may be unnecessary/undesired if you want to accept things like whitespace / don't want to depend on the system's locale.

This give error in script:Enter the password: UI((98kk Traceback (most recent call last): File "new.py", line 22, in passw_check() File "new.py", line 17, in passw_check if validate(passin): File "new.py", line 10, in validate if sum(map(is_punc, s)) != 2: return False File "new.py", line 5, in is_punc def is_punc(c): return c in string.punctuation NameError: global name 'string' is not defined — sunp, Apr 04 '15 at 15:21
@sunnyp. a previous edit of the answer omitted the `import string` at the top, try it again with that line. — jedwards, Apr 04 '15 at 15:22
yep it was 'import string' that was missing. Now working perfectly. Thanks. — sunp, Apr 04 '15 at 15:30

AChampion · Answer 3 · 2015-04-04T15:40:35.150

You could use regex, this should validate that the passin has 2 lower, 2 upper, 2 digits and 2 specials (you can change:

import re, string
def passw_check(passin):
    lower = "(?=.*[a-z].*[a-z])"
    upper = "(?=.*[A-Z].*[A-Z])"
    digit = "(?=.*[0-9].*[0-9])"
    special = "(?=.*[{0}].*[{0}])".format(re.escape(string.punctuation))
    return re.match("^.*{}{}{}{}.*$".format(lower, upper, digit, special), passin)

check = passw_check(raw_input("Enter the password"))
print("Password Okay" if check else "Not Okay!")

python script to accept 8 char password with these conditions only: 2 num, 2 upper, 2 lower, and 2 special

3 Answers3